I agree with some of the others; the cheapest, simplest, easiest is to repair/rebuild your engine or replace with another one of the same. A V8 conversion is a big deal, especially if it is a 3100 1/2-ton as it has a torque-tube rear axle and drive shaft and that will have to be replaced too...
Get another mechanic. Lots of guys claim to know all about old cars/trucks - but if your truck has a 54 235 then it doesn't have "bobble" or babbited rods.
Start reading: http://chevy.oldcarmanualproject.com/shop/1954truck/index.html
Great looking truck. I think it looks like a 3/4-ton. Good luck with it.

OH, wetwilly, all Chevy 6-cylinders from the first ones in 1929 had an oil pump. They did have dippers on the rods and troughs and nozzles in the pan to lube the rod bearings. Those bearings were babbit cast into the big end of the rods. 1953 was the last year for that.

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